Highly efficient one pot synthesis of benzimidazoles from 2-nitroaniline and PhSiH3 as reducing agent catalyzed by Pd/C as a heterogeneous catalyst

• Efficient route for synthesis of benzimidazole has been developed using CO 2 . • Pd/C as a efficient, reusable catalyst has been used for synthesis of benzimidazole. • The PhSiH 3 is used as moisture stable reducing agent. • This catalytic system shows direct conversion of o-nitroaniline to benzimidazole. • Good to excellent yields were obtained with excellent functional group tolerance. This work reports an efficient route for the synthesis of benzimidazole from o-nitroaniline in the presence of carbon dioxide atmosphere, PhSiH 3 as a reducing agent catalyzed by Pd/C as a catalyst. Benzimidazoles have become the focus of organic chemists, as benzimidazole is an important intermediate in medicinal chemistry. We have developed more efficient route for the synthesis benzimidazole and various substituted benzimidazoles have been synthesized in good to excellent yield. The TBD (1,5,7-Triazabicyclo [4.4.0] dec-5-ene) is selected as a base as it promotes the CO 2 insertion. Benzimidazoles were synthesized through reduction of nitro group followed by cyclization of amine using CO 2 as a carbon source. Moreover, the Pd/C catalyst can be recycled up to five recycle run without significant changes in the yield of the product.